Health care workers can be exposed to patients with infections. To minimize exposure to airborne biological agents, health care facilities use isolation rooms, negative pressure ventilation, air filtration and disinfection. However, in certain settings administrative and engineering controls may not adequately protect health care workers from contaminated airborne droplets. Therefore health care workers should use respiratory protection.
Health care workers routinely use surgical masks as part of their personal protective equipment. However, surgical masks are not respirators and are not certified as such. They do not protect the wearer from inhaling small particles that can remain airborne for long periods of time. Surgical masks are effective barriers for retaining large droplets which can be released from the wearer through talking, coughing, or sneezing. Surgical masks are useful in many patient care areas. In fact, they may reduce wound site contamination during surgical or dental procedures. But surgical masks can not be used as a protection from many hazardous airborne materials. The filter material of surgical masks does not retain or filter out submicron particles. In addition surgical masks are not designed to eliminate air leakage around the edges.
Respirators used in health care settings should be selected according to the efficiency of respirator filters in filtering aerosols and according to the type of procedure to be carried out.
One of the most common respirators used in health care facilities is the type N95 disposable respirator. These used to be called dust/fume/mist (DFM) masks that were certified under an previous standard. N95 filters belong to a group of air purifying particulate filters. NIOSH (National Institute for Occupational Safety and Health in the U.S.) certifies these respirators (and other respirators) and these certified products are used in Canada.
The "N95" is one of three types of filters - N, R and P. These refer to the type of resistance they have to the degrading of their filtering efficiency. When exposed to different kinds of airborne particulates, mists, etc. To help people remember which filters can be used for protection against different kinds of airborne particulates (e.g. dust, fume and mist). NIOSH provides the following guide:
N - Not resistant to oil
R - Resistant to oil
P - Oil proof
The "95" in N95 refers to the filter efficiency. There are three levels of filter efficiencies - 95% (N95), 99% (N99), and 99.97% (N100 or HEPA filter) tested against aerosol (fine mist) droplets 0.3 microns in diameter. N95 type respirators are the respirators recommended by Health Canada and the U.S. Centers for Disease Control and Prevention (CDC) for use by health care workers in contact with patients with infections that are transmitted from inhaling airborne droplets (e.g., tuberculosis (TB); also recommended for health care staff working with patients having or suspected of having SARS, severe acute respiratory syndrome).
High risk procedures such as bronchoscopy and autopsy require additional protection. For example, protection may include full facepiece negative-pressure respirator, powered air-purifying respirators, and positive pressure airline respirators equipped with a half-mask or full facepiece. A supplied-air respirator with a hood may be needed for staff who cannot be properly fitted with respirators with a facepiece. In medical procedures that generate aerosol mists, goggles or face shields should also be used to prevent eye contamination.
Laser Plumes - Health Care Facilities has some additional, related information on controlling exposure to certain airborne contaminants in health care facilities.
If health care workers need to use a respirator then a respiratory protection program is necessary. The program should include the following procedures for:
Other OSH Answers documents Designing an Effective PPE Program, Respirator Selection and Respirator Care have additional informational information that will assist in setting up a respiratory protection program.
Document last updated on June 9, 2003